Department of Integrative Brain Science, Graduate School of Medicine, Kyoto University, Japan.
J Neurophysiol. 2011 Apr;105(4):1531-45. doi: 10.1152/jn.00511.2010. Epub 2011 Jan 27.
When tracking a moving target in the natural world with pursuit eye movement, our visual system must compensate for the self-induced retinal slip of the visual features in the background to enable us to perceive their actual motion. We previously reported that the speed of the background stimulus in space is represented by dorsal medial superior temporal (MSTd) neurons in the monkey cortex, which compensate for retinal image motion resulting from eye movements when the direction of the pursuit and background motion are parallel to the preferred direction of each neuron. To further characterize the compensation observed in the MSTd responses to the background motion, we recorded single unit activities in cortical areas middle temporal (MT) and MSTd, and we selected neurons responsive to a large-field visual stimulus. We studied their responses to the large-field stimulus in the background while monkeys pursued a moving target and while fixated a stationary target. We investigated whether compensation for retinal image motion of the background depended on the speed of pursuit. We also asked whether the directional selectivity of each neuron in relation to the external world remained the same even during pursuit and whether compensation for retinal image motion occurred irrespective of the direction of the pursuit. We found that the majority of the MSTd neurons responded to the visual motion in space by compensating for the image motion on the retina resulting from the pursuit regardless of pursuit speed and direction, whereas most of the MT neurons responded in relation to the genuine retinal image motion.
当我们在自然环境中用追踪眼动追踪移动目标时，我们的视觉系统必须补偿背景中视觉特征的自身诱导视网膜滑移，以使我们能够感知它们的实际运动。我们之前曾报道过，猴子大脑皮层中的背内侧上颞（MSTd）神经元代表了空间中背景刺激的速度，当追踪和背景运动的方向与每个神经元的最佳方向平行时，这些神经元会补偿由于眼球运动而导致的视网膜图像运动。为了进一步描述 MSTd 对背景运动反应中观察到的补偿，我们记录了皮质区域中颞（MT）和 MSTd 中的单个单位活动，并选择了对大视野视觉刺激有反应的神经元。当猴子追踪移动目标和注视静止目标时，我们研究了它们对背景中大视野刺激的反应。我们研究了背景中视网膜图像运动补偿是否取决于追踪速度。我们还询问了每个神经元与外部世界的方向选择性是否即使在追踪过程中也保持不变，以及视网膜图像运动补偿是否发生与追踪方向无关。我们发现，大多数 MSTd 神经元通过补偿由于追踪而导致的视网膜上的图像运动来对空间中的视觉运动做出反应，而不管追踪速度和方向如何，而大多数 MT 神经元则与真实的视网膜图像运动有关。
